Contact printer



May 27, 1947.

C. H. JACOBSON CONTACT PRINTER Filed Feb.` 19. 1944 2 Sheets-Sheet lDMW@ ATTORNEY May 27, 1947- c. H. JAcoBsoN CONTACT PRINTER Filed Feb.19, 1944 2 Sheets-Sheet 2 .ml a.

D 44, wv QW ATTORNEY Patented May 27, 1947 CONTACT PRINTER Carl H.Jacobson, Binghamton, N. Y., assignor to General Aniline & FilmCorporation, New York, N. Y., a corporation of Delaware ApplicationFebruary 19, 1944, Serial No. 523,001

s claims. 1

This invention relates to contact printing mechanisms, more especially,to the construction of such mechanisms so as to illuminate the negativeand printing material with an even distribution of light, and toimprovements in the platen for holding the negative and printingmaterial fiat and in contact during printing.

Contact printers of this type are normally provided with a glass throughwhich light is projected and this glass is flat or planar, evendistribution of the light being obtained in so far as possible, byfinishing the inside of the printer with aluminum paint or in some otherway, providing for diffusing and reflecting the light upwardly through aglass window to the negative and printing material. The source of lightis kept as far from the glass window as Ipracticable, but evening theillumination that way is difficult unless the size-of the mechanism isincreased beyond practical dimensions. According to the invention hereindescribed, a window is employed which is curved in one plane, the radiusof curvature being centered at approximately the source of light. Thisassures even illumination at the sides of the negative and printingmaterial as well as at the central portions, that is, considering oneplane only. To compensate in the other plane, if an elongated coaxiallight source is not used, a curved reflector serves to distribute thelight evenly in such a manner that the sides of the negative andprinting material are illuminated with a light of practically the sameintensity as the central portions.

In printing it is always desirable to hold the negative flatly orsmoothly against the window and also to maintain the printing materialin absolute contact with the negative and free from wrinkles and otherdistortions such as would affect the quality of the print obtained. Toaccomplish this a platen has been so designed that it progressivelyengages the paper or other printing material after the same has beenplaced in contact with a negative to be printed; it also imparts anironing effect as it is closed. The platen in the form of a belt ofrubber or other resilient and preferably stretchable material, is socontrolled that as it is closed or pressed down over the transparentwindow, one end of the paper and negative will be engaged and then theelastic belt will be stretched and progressively brought into contactwith the remaining surface of the printing material. The belt is passedover rollers carried by a system of levers hinged in such a manner as toimpart to the belt the proper degree of stretch and to cause it to berolled over and to iron the paper onto the negative in a manner to bedescribed in greater detail in the following paragraphs.

The invention will be described with respect to one embodiment of thesame illustrated in the accompanying figures of drawings in which:

Figure 1 is a section through a contact printer embodying the invention,the platen being raised or withdrawn from the printing material.

Figure 2 is a similar section in which the platen has been closed as itwould be when the negative and printing material are subjected to light.

Figure 3 is an elevation of'the front of the printer with the platen inraised position.

Figure 4 is a plan View, the platen being closed.

Figure 5 is a section at line 5-5, Figure 2.

Now referring to Figures 1 and 2, the printer consists of a box-likestructure I0 made of wood, metal or plastics and being light tightexcept for a translucent window II set in the top surface of theprinter. V This window may be of frosted or diffusing type glass. Asource of light l2 is provided and may be a tungsten lamp of the usualtype, preferably with a frosted glass bulb or a bulb of the elongatedtubular type. This lamp is held within a socket I3 and by suitableconnections (not shown) to a source of current, will be lighted whencontact is made Within a switch I4. Normally such a printer is merelyplugged in the usual Wall type outlet and operates from the ordinaryvolt circuit.

The window Il, preferably of a type of glass adapted to diffuse thelight passing through it, is curved in one plane, the center of itsradius of curvature being located at about the center of the lightsource. As shown in Figure 3, especially in the case where a point lightsource is utilized, the bottom of the printer is provided with areflector I 5 which is curved in one plane, the curvature of thisreflector being in a plane opposite or perpendicular to the plane inwhich the transparent window Il is curved. The entire surface at theinside of the printer is painted or otherwise finished with a reflectingmaterial such as aluminum paint thereby to flood the window with as muchlight as possible. The curvature of the window itself provides evenillumination of the negative and printing material in one plane and thecurved reflector I5 serves that purpose in the plane perpendicular tothe plane of window curvature.

Masking blades are provided so that margins may be formed at the edgesof the prints and to determine the portion of any negative which is tobe printed. One set of blades IS is mounted in slides I'I which areretained in position by the usual springs. These blades I6 are curved tocorrespond with the surface of the glass Window Il and may be arrangedabove or beneath the opposite pair of blades I8 which serve to mask thenegative at the edges not covered by blades I6. Blades I8 are fixed toradial arms I9, there being two such arms at either side of the printeralthough in certain instances arms at one side only may suffice. Thesearms are pivoted at which is the same center about which the transparentwindow is curved. As the arms I9 are swung about the pivot 20, theblades move to cover different portions of the window II. Blades IB maybe curved to fit the surface of the window.

The platen is caused to cover or uncover the transparent window as anoperating handle 2I is lowered or raised. This handle projectstransversely of the printer and between the parallel sides of a platencarrier 22, each of which is pivoted as at 23 to a link 24. The link 24pivots at 25 to lugs 26 bent upwardly from a piece of strip steel orother suitable material. This strip projects along the top of theprinting closure at 21 and is fixed thereto by rivets 28 or othersuitable attaching means.

A latch 29 is formed by bending a piece of strip spring steel asillustrated in Figure 2, this strip of steel also continuing about thehandle and serving as a means for pushing in the plunger 30 of theswitch I4 whenever the platen is closed. The strip material passes aboutthe handle 2| and is doubled as at 3l for engaging the plunger. The bentend of the latch 29 engages a. catch 32. Whenever it is desired to stopthe exposure and raise the platen, the operator merely presses againstthe latch 29 releasing it, whereupon the resiliency in the platen willlift it slightly thereby allowing the plunger 30 to return to itsoriginal position turning off the light. The entire platen assembly -maythen be raised.

The platen consists of a belt 33 preferably of resilient, flexible andstretchable material such as rubber. However, other materials may beused, for example, the belt may be of a laminated construction in whichrubber and fabric are combined. The surface of the belt should be of atype adapted to conform to the surface to be covered thereby to confinethe light and to retain the negative and printing paper in a flattenedand perfectly contacting relationship. If desired, the belt may be ofrubber or other material and its surface covered with softer rubber suchas sponge rubber or with felt or plush material.

The beit 33 passes about a plurality of rollers, the rst being a roller34 extending between links 24. This roller is preferably held againstturning on its axis and thus serves to maintain the adjacent portion ofthe platen belt in a relatively xed position. In other words, fixingroller 34 friotionally retards movement of the adjacent portion of belt33 so that the negative and printing material may be held at their upperends and the ironing and rolling action of the belt progressed from thatpoint.

A roller 35 extends across between the sides of platen carrier 22 and isfreely rotatable on its axis. Roller 36 is freely rotatable on an axisbut that axis is retained at its ends by parallel arms or levers 31which are hinged at the axis of roller 35. Another pair of arms 33 arelikewise hinged at the axis of roller 34 and connect to the first 4mentioned levers 31 by the engagement of shouldered rivets 39 withinslots 40.

The length of these arms 31 and 38, and the centers about which theypivot, in combination with the carrier 22 movable about pivot 23, issuch as to cause stretching of the belt 33 as the platen is closed, butallows it to contract as the handle 2I is lifted to the position ofFigure l. By suitably designing this system of levers, any desiredamount of stretch in the belt can be obtained, or if desired, theconstruction may be such that there will be no stretch provided for andthe only action of the platen will be that of flattening or ironing asit is progressively rolled over the surface of the printing material.

While it has not been shown here, a safe light is to be provided withinthe printer casing and the electrical connections are such that when theprinter is being used, the safe light will be lighted continuously. Ofcourse, the printing lamp I2 is lighted only when a contact is madewithin the switch I4. The platen is especially adapted to use with acurved window such as window I I, but it is to be understood that theplaten may be used to advantage in printers having the usual planarwindow, the levers and their pivots being proportioned for action withthat particular type of surface. The masking blades and their supportingmeans are especially useful with a curved window and would be usedregardless of whether the platen were of a type as described here, or ofsome other type.

In operation, the printer is set up and the electrical connectionplugged into some suitable source of current. That cause's the safelight to be lighted whereupon a negative is placed on the window l I andthe masking blades are moved along the surface of the window to coverthe edges of the negative masking off that part thereof which it is notdesired to print, or at least, defining the edges of the actual imagethe negative. A sheet of printing material such as the usual contactprinting paper is then superimposed upon the negative and above themasking blades whereupon the operator, by means of handle 2I, lowers theplaten. Starting from the position of Figure 1 the links or levers 31and 38 separate the rollers 34, 35 and 36 thereby stretching the belt 33and rolling it over the paper. Since the roller 34 is not allowed toturn on its axis, that end of the belt is maintained substantially fixedrelatively to the surface of the window and as the top edge of the paperis gripped by the surface of the belt, that edge will be held or pressedagainst the negative or against the masking blades so that the ironingaction progresses from that point. After the belt has reached its extentof travel, the contact member 3I engages the switch plunger 30 andy moreor less simultaneously, the latch 29 engages projection 32 locking theplaten assembly in the position shown in Figure 2. During that time thelight I2 remains lighted thereby subjecting that part of the negativeand a corresponding area of the printing paper contained within themasking blades to the action of the printing light. Then the platenassembly can be raised whereupon the printing paper is removed andaccording to the usual practice will be developed and subjected to otherappropriate treatment.

The invention has been described by reference to a more or less specificexample and, of course, many variations will occur to those skilled Inthis art, but will fall within the scope of the invention as originallyconceived. The term flattened or flattening has been used in describingthe action of the belt 33 as it is rolled or progressed over the surfaceof the printing material, and that term is employed without a specialreference to a plane surface since the Window II is curved in acylindrical manner. It is to be understood that the platen belt ironsand fiattens out Wrinkles or imperfections tending to arise in the paperor negative whether the printing surface or window be of planar orcurved construction.

The invention is not to be limited other than by the scope of theappended claims.

I claim:

1. A contact printer having in combination, a frame, a light source, acurved window and masking blades, one set of said blades being curved toconform to the curvature of the Window' and the other set being movablealong the curved window surface by pivoting them at the center ofcurvature of said window.

2. A contact printer having in combination, a frame, a light source, acurved window and masking blades, one set of said blades being curved toconform to the curvature of the Window and being slidable along thesurface of said window, the other set of blades being straight andmounted to swing on radial supports pivoted at the center of curvatureof the window.

3. A contact printer having in combination, a frame, a light source, awindow and a platen for pressing a sheet of sensitized paper and anegative against said window, said platen comprising an endless, elasticbelt, a series of rollers over which said belt is passed and a system oflevers for supporting said rollers so pivoted and proportioned that asthe platen is moved to engage the paper and negative, contact is ilrstmade at one end of the paper and then the resilient belt isprogressively stretched and rolled over the paper surface.

4. A contact printer having in combination, a frame, a light source, acurved window having its center of curvature at substantially the centerof the light source and a platen i'or pressing a sheet of sensitizedpaper and a negative against said window, said platen comprising anendless elastic belt, a series oi.' rollers over which said belt ispassed and a system of levers for supporting said rollers so pivoted andproportioned that as the platen is moved to engage the paper andnegative, contact is first made at one end of the paper and then theresilient belt is progressively stretched and rolled over the papersurface.

5. A contact printer having in combination, a frame, a light source, acurved window, masking blades for said window and a platen for pressinga sheet of sensitized printing paper and a nega tive into contact withsaid window, said platen having hinges, interconnected levers, anoperating handle and guiding rollers over which is passed a resilient,endless belt, the construction being such that when said operatinghandle is moved to close the platen, the levers are spread to stretchand progressively roll the belt over the paper and negative to iron themagainst the windoW surface, and when opened, said levers are folded torelax the belt and lift it from the paper and negative.

6. A platen for a contact type printer having in combination a platencarrier adapted to be hinged to a printer frame, an operating handle,interconnected pivoted levers at either side of said platen carrier andconnections between them including rollers, and a flexible, resilient,endless belt passed about and retained by said rollers and between saidlevers.

7. A contact printer having in combination, a frame, a light source, awindow and a platen for pressing a sheet of sensitized paper and anegative against said window, said platen being formed as an endlessbelt of resilient material, and means for retaining and guiding saidbelt which includes a plurality of rollers and supporting means for saidrollers including an articulated linkage by which said rollers arespaced and by which they may be so controlled as to cause the belt ofresilient material to hold one edge of the paper and negative in placeon the window and progressively to make contact across the paper andnegative for smoothing and flattening the paper and negative against thewindoW.

8. A contact printer having in combination, a frame, a light source, aWindow and a platen for pressing a sheet of sensitized paper and anegative against said window, said platen comprising an endless belt offlexible material, rollers upon which said belt is retained and guidedand an articulated linkage for supporting said rollers and for movingthem to different positions for progressively rolling the belt over thepaper and negative to be printed and for removing the belt from contacttherewith.

CARL H. JACOBSON.

REFERENCES CITED The following references are of record in the ille ofthis patent:

UNITED STATES PATENTS

